Guard for shaper heads



July 23, 1929.

c. J. NELSON 1,721,708

GUARD FOR SHAPER HEADS Filed Feb. 20, 1928 2 Sheets-Sheet l INVENTOR.

ATTORNEY.

July 23, 1929. c, NELSON 1,721,708

GUARD FOR SHAPER HEADS Patented July 23, 1929.

UNITED STATES CARL JOHN NELSON, OF BERKLEY, MICHIGAN.

GUARD FOR SHAPER HEADS.

Application filed February 20, 1928.

This invention relates to guards for enclosing vertical wood shapers,which rotate at very high speeds, to prevent injury to the operators,and thereby not only to protect the operators but to relieve them of thesevere mental tension which reduces their efliciency to such an extentthat their output falls off seriously during the later hours of theworking day. The contant danger from unprotected cutting tools of thischaracter is so great that the operators involuntarily slow down becauseof mental strain long before physical fatigue sets in, as has beendemonstrated by comparisons of results obtained with the same machinesbefore and after my guards for theshaper heads were installed.

This invention consists of a guard shell which normally encloses theshaper-head and the knives mounted thereon until the work is movedtoward it and then rises to uncover the shaper knives to a predeterminedextent to permit the operator to press the work against the cutters, theguard coming down to protective position as soon as the work is movedaway from the cutters, in combination with pneumatic means for actuatingthe guard and a pneumatic valve which is actuated by the work and whichcontrolsfthe operation of the guard.

It further consists of the details of construction illustrated in theaccompanying drawings and particularly pointed out in the claims.

In the accompanying drawings, Fig. 1, is a plan of a wood shaperequipped with any novel guard. Fig. 2, is an elevation of this guard,the shaper head being shown in dotted lines. Fig. 3, is a section on theline 33 of Fig. 2. Fig. 4, is a vertical section of the actuatingmechanism for the guard. Fig. 5, is a vertical section of the controlvalve.

Similar reference characters refer to like parts throughout the severalviews.

The well known cutter head 1 shown in plan in Fi 1 is usuallyrectangular in crosssection an to it are attached the knives 2, the headbeing mounted on a shaft 3 which projects upwardly from the table 4. Theupper end of the shaft is journaled in a bracket 5 carried by a post 6which projects upward from a base 7 secured to the table 4. As theseheads rotate as high as eight to ten thousand rotations per minute, thedanger Serial No. 255,542.

to the hands and arms of the operators is apparent, especially wherework is duplicated to such an extent that the operations becomemechanical.

In my novel construction, a hub 10 is at-, tached to the base 7 and around vertical post 11 is mounted in this hub. The upper end 12 of thepost is reduced in diameter and on the lower end is slidable a head 13carrying a key 14 slidable in a key-way 15 shown by a dotted line inFig. 4, and this key is positioned by the pins 16 and screw 17. A secondhead 18 is slidable on the upper end of the post and is provided with astuffing box 19. A cylinder 21 is held between the heads by means of'four bolts 20. The lower head is provided with a vent passage 23 toprevent air being compressed in the lower end of the cylinder.

A piston is mounted on the'post and consists of two disks 24 pressedtoward each other by a nut 25 and a packing ring 26 is held between thebeveled edges of the disks and pressed against the .interior wall of thecylinder. Air under pressure is conducted to the longitudinal bore 27 ofthe post by a pipe 28 and flows into the space above the piston throughpassages 29 above the piston and raises the cylinder and the heads. Thismovement is limited by an adjustable clamp 30 shown in Figure 3.,

The heads are preferably square in plan and the shell 33 is secured tothese heads by screws 36, being formed of two parallel sides 32 and asemi-cylindrical end 34. A reinforcing strap 35 and two short plates 37may be used, if desired. The guard is elevated by air pressure butdescendsby its own weight, the fall being cushioned by a rubber collar38. The movements of the guard are controlled by the valve shown in Fig.5.

A valve body 40 is provided with a cylindrical lining 41, held inposition by means of the collars 42 and 43. The pipe 44 connects to asource of air under pressure while the pipe 28 connects to the guard. Acylindrical valve 45 has a circumferential groove 51 which connects theports 46 and 46 when the valve is depressed by work sliding on the table4 coming in contact with the rounded knob 48 which is adjustably mountedon the valve. The lower end of the valve is formed with a central bore52 which receives a spring 49 and with an exhaust port 50 which connectsto this central bore. The lower colwhen not in use.

lar 43 has an exhaust opening 53 to permit air passing from the pipe 28through the port and bore- 52 toescape to the atmosphere.

The parts are normally in the position shown in the drawings. When workis slid on the table toward the shaper head, it passes over the button48 and depresses it against the pressure of the light spring 49. Airrushes from the pipe 44 through port 46, grove 51, second port 46, pipe28, passage 27 in post'll and passages 29 into the space between thepiston 24 and head 18 and forces the guard up until it is stopped by theclamp 30'. lVhen the Work is finished,

it'is moved back from over the button 48 which permits'the spring 49 toraise the valve. The airin the cylinder-now escapes through the passages29 and 27, pipe 28, ports 46 and 50, bore 52 and opening 53 to theatmosphere, permitting the guard to slide down over the shaper head.movements of the guard are very rapid so that. the shaper head isenclosed'at all times The position of the but ton 48- relative 'to theshaper head will be determined by the character ot'the work.

The details of construction'and the proportion of the parts may all bechanged by those skilled in the art without departing from the spiritofmy invention as set forth in the following claims.

1. A guard for a shaper head comprising a vertically movable shelladapted toenclose said head, a vertical post having a. 1011-- gitudinalpassage, a cylinder, heads at the ends. of the cylinder slidable on thepost, a

piston for the cylinder secured to the post, 1

a valve adapted to be. positioned by the Work presented to the cutterhead, a pipe connecting the valve to a source of air under pressure anda pipe connecting the valve to thepassage in said post.

2.A guard for a shaper head comprising a vertically movable shelladapted to enclose said head, a cylinder attached to the shell, a

piston within the cylinder, a hollow piston.

rod: and. a: pipe connecting thereto to permit The move said valve.

air to pass into and out of the cylinder to cause it to move up, a valvebody adjacent the cutter head having a vertical bore and two ports, apipe connecting to a source of air under pressure and to one of saidports, the other port connecting to said piston rod by said first namedpipe, a valve slidable within said valve body and provided with atransverse passage which connects said ports when depressed and with anexhaust passage which connects to the second named port when said valveis elevated, a spring to elevate the valve, and a button attached to theupper end of the valve and adapted to be depressed by Work beingpresented to the shaper head. 1

3. A guard for a shaper head comprising a vertically movable shellhaving parallel sides and a semi-cylindrical end adapted to enclose saidhead, a vertical post having a longitudinal bore, a-cylind'er,rectangular heads at the ends of the cylinder slidable onsa-id post towhich heads the parallel sides of theshell are attached,'a piston forsaid cylinder attached to said post Whose bore terminates above saidpiston, and a Valve tocontrol the flow of air under pressure to the boreof said post.

4-. A guard for a'shaper head comprising a stationary part and avertically movable part, said part-s embodying an air cylinder and apiston therein, means to conduct air to and from said cylinder, a valvebody ad jacent the shaper head, a piston valfve therein, pipesconnecting said valve body to the guard and to a source of air underpressure, and means 1n the path of the work to 5. A guard for ashaperhead comprising a stationary part and a vertically movable part, saidparts embodying a cylinder and a piston therein, means to conduct fluidunder pressure to and from said cylinder, a valve mechanism adjacent theshaper head, pipes connecting said valve mechanism to the guard and to asource of fluid under pressure, and means in the path: of the work tooperate the valve mechanism.

CARL JOHN NELSON.

